Ooh ooh, and because the twin was in space, he's going to be younger than the one who stayed on Earth, right? Despite being twins, one is going to look like the father of the other one, and then some really interesting things is going to happen and…
Staying 340 days at the ISS, which does 7667 m/s, he's going to be younger by… (compute compute) a hundredth of a second. Hmpf…
…Never mind, then.